1. Field of the Invention
Embodiments of the present invention provide a memory cell, a memory with a memory cell and a method for writing data in a memory cell.
2. Description of the Related Art
Memory cells comprising a solid state electrolyte material are known as programmable metallization memory cells (PMC memory cells). Memory devices including such PMC memory cells are known as conductive bridging random access memory devices (CBRAM). Storing of different states in a PMC memory cell is based on the development or diminishing of a conductive path in the electrolyte material between electrodes based on an applied electric field. Although the electrolyte material may typically have a high resistance, the conductive path between electrodes may be adjusted to lower resistance. Thus, the PMC memory cell may be set to different states depending on the resistance of the PMC memory cell. Typically, both states of the PMC memory cell are sufficiently time-stable in such a way that data may permanently be stored.
A PMC memory cell is typically operated by applying a positive or a negative voltage to the solid state electrolyte layer. To store data in the PMC memory cell, the PMC memory cell is brought to the program state by applying a suitable programming voltage to the PMC memory cell which results in the creation of the conductive path in the solid state electrolyte material which may correspond to the setting of a first state with low resistance. In order to store a second state in the PMC memory cell with high resistance, an erase voltage may be supplied in such a manner that a resistance of the PMC memory cell changes back to a high resistance which may correspond to the second state (erased state). To read out a data from the PMC memory cell, a read voltage may be applied which may be lower than the programming voltage. With the read voltage, a current through the resistance of the PMC memory cell may be detected and associated with the respective low or high resistance state of the PMC memory cell.
The programming of the PMC memory cell depends on the current and the duration of the current. The resistance of the PMC memory cell depends on the value of the current and the duration of the current. Therefore, the program state of the PMC memory cell and a long term stability of the function of the PMC memory cell depends on the writing operation.
What is needed is an improved memory cell, an improved memory and an improved method for writing data in a memory cell.
It will be appreciated that elements in the Figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements and the Figures may be exaggerated relative to other elements to help the understanding of embodiments of the present invention.